Residual-Based Multiscale Models for Large-Eddy Simulation of Turbulence

Variational multiscale concepts are used to construct subgrid-scale models for Large-Eddy Simulation (LES) of turbulence. The basic idea of this framework is to introduce, a priori, a decomposition of the solution into coarse and fine scales. The coarse scales are identified with the numerical approximation, while the fine scales are identified with the subgrid scales and need to be modeled. A residual-based fine-scale approximation is proposed by extending to the nonlinear realm algebraic approximations of the Green's function. These approximations, based on the theory of Stabilized Methods, may be thought of as the modeling component of the proposed approach. This new modeling concept is very different from the classical LES modeling ideas, which are dominated by the addition of eddy viscosities. Applications of the approach are presented.